On the ecto-(a) they keepy there packs in the back of the ectomobile. Did the stands really hold the packs in place or were they just there for show? I looked at the kicks of the stands on this sites reference page and it just doesn’t logival that they could actually keep the packs in place.
Well… There was never any need for them to be functional, what with it being a movie and all.
Are they capable of holding the packs steady? Well if they were strapped to the holders, like most people do with their replica ectos, then yes.